Kibblewhite Precision Valve Kit 20-23000Full set of Black Diamond stainless steel standard size valves for engine applications listed All valves are impregnated by a special process to a depth of . 002in. with a surface buildup of . 0002in. This process improves wear properties, reduces friction and provides resistance to corrosion and wear Compatible with leaded and unleaded fuels Sold as complete kits for one engine Made in the U. S. A.